Actually, it looks nothing like the concept imo. These are just pics of a mule, so there might be slight changes, trim, wheels, rear wiper etc., but it will look ALOT like this...
Sir , what you posted is what you rightfully said ........ a mule. It is simply a shell to house the new powertrain components . It is plain to see that this body is of the outgoing 6 with adjustments made to house the new engine etc. Nice research though.
The 2014 mazda6 will be unveiled probably later this year. Currently Mazda has a few short teaser videos on facebook showing the new 6 [the actual 6, not takeri]: http://www.facebook.com/Mazda